Whey permeate and slurry are both from the dairy farm animals while whey is characterised with high acidity the slurry is mildly alkaline, and they are both biodegradable. In this study, a lab-scale partitioned up-flow anaerobic digestion tank was used to achieve a suitable feeding regime for co-fermenting whey permeate and slurry. The partitioned up-flow anaerobic digestion tank provided a stable treatment performance with over 95% of sugar reduction and a total volatile fatty acid concentration under 150 mg/L The ripely ratio of the reactor was below 0.4 which suggest strong buffering stability. Biogas production surged with an increase in the feeding regime from 1:1 to 4:1 with a maximum value of 3.5 Lid. This was not the case for the methane content which continued to reduce as the feeding regime increased from 2:1 to 4:1. The feeding regime of 2:1 recorded the highest methane composition between 40 and 50% which suggests this is the best feeding regime for co-fermenting whey permeate and slurry using a partitioned up-flow anaerobic digestion tank. (C) 2019 Elsevier Ltd. All rights reserved.